Superabsorbent materials for use in hygiene products, which arc based on polysaccharides such as cellulose and starch, have recently become widely known in the art, for example in WO 98/27117. The absorbing capacity of such materials can be increased by crosslinking the polymers, e.g. by using epichlorohydrin, diglycidyl ethers, divinyl sulphone or other commonly known crosslinkers capable of reacting with hydroxyl groups, or by using carboxylated polysaccharides and crosslinkers capable of reacting with carboxyl groups, such as divalent metals. However, there is a demand for thinner absorbent products, which implies that superabsorbent materials have to be found which have further increased absorbing capacity and have increased flexibility.
WO 97/19116 describes superabsorbent acrylic polymers which are crosslinlked by polymerisation of acrylic acid in the presence of a combination of trimethylolpropane triacrylate or triallylamine, polyethyleneglycol mono(meth)acrylate monoallyl ether and polyethyleneglycol mono(meth)acrylate monoalkyl ether.
WO 97/31971 discloses similar, foamed superabsorbent acrylic polymers which are crosslinked e.g. with trimethytolpropane triacrylate, to which internal or external plasticisers (e.g. glycerol or acrylic esters) may added to increase flexibility of the foam.